Ink Jet Printable Compositions

ABSTRACT

In jet printable compositions that include nano metal powders in a liquid carrier.

BACKGROUND

Ink jet printing is a widely used printing technique. Specific examplesinclude continuous ink j et printing and drop on demand ink jetprinting.

SUMMARY

We have developed compositions that can be ink jetted to form conductivepatterns on a variety of substrates. Dispersions hereby are nano metalpowders dispersed in a liquid carrier. Inks are dispersions withadditional additives to impart additional properties to the dispersionin order to fulfill requirements of the printing process and the finalproduct properties. The final printed product is in the form of aconductive pattern that may have additional properties depending on itsspecific application. The nano metal powders, which are produced by theMetallurgic Chemical Process (MCP) process described herein, havespecial properties, enabling the dispersion and de-agglomeration of thepowder in a liquid carrier (organic solvent, water, or any combinationthereof), with or without additives. Taking advantage of theseattributes we have been able, with the MCP-produced nano metal powders,to design compositions with very low viscosities, as required for inkjet printing at high metal concentrations, by selecting appropriatecombinations of the nano metal powder, liquid carrier, and, optionally,additives. The ability to combine high metal concentrations with verylow viscosities makes the compositions particularly useful for ink jetprinting.

Dispersions comprising nano metal particles dispersed substantiallyhomogeneously in a liquid carrier that includes (a) water, awater-miscible organic solvent, or combination thereof or (b) an organicsolvent, or combination of organic solvents and (c) surfactants, wettingagents, stabilizers, humectants, rheological agents, and combinationsthereof, are described.

Inks based upon these dispersions, and further includingproperty-modifiying additives (e.g. adhesion promoters, rheologyadjusting additives, and the like) are also described.

The compositions have properties that enable their jettability (printingthrough ink jet print heads which posses small nozzles, usually in themicron range). These properties include the following: low viscositiesbetween 1 and 200 cP (at room temperature or at jetting temperature),surface tension between 20-37 dyne/cm for solvent based dispersions and30-60 dyne/cm for water based dispersions, metal loadings of nanoparticles between 1% and 70% (weight by weight), low particle sizedistribution of the nano metal particle material having a particle sizedistribution (PSD) D90 below 150 nm, preferably below 80 nm. Thecompositions have stabilities sufficient to enable jetting with minimumsettling, and without clogging the print head or changing the propertiesof the compositions. The compositions can be printed by differenttechnologies including continuous ink jet technologies, drop on demandink jet technologies (such as piezo and thermal) and also additionaltechniques like air brush, flexo, electrostatic deposition, wax hotmelt, etc.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is a representative ink jet printed pattern.

FIGS. 2-6 are Scanning Electron Microscopy (SEM) photographs of nanometal particles used to prepare the ink jettable compositions.

FIGS. 7-8 are Transmission Electron Microscopy (TEM) photographs of inkjettable compositions.

FIG. 9 is an x-ray diffraction scan of nano metal particles used toprepare ink jettable compositions.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

The ink jettable compositions feature nano metal particles in a liquidcarrier. Suitable nano metal particles include silver, silver-copperalloys, silver-palladium alloys, and other metals and metal alloysproduced by the process described in U.S. Pat. No. 5,476,535 (“Method ofproducing high purity ultra-fine metal powder”) and PCT application WO2004/000491 A2 (“A Method for the Production of Highly Pure MetallicNano-Powders and Nano-Powders Produced Thereof”), both of which arehereby incorporated by reference in their entirety. The nano metalparticles have a “non uniform spherical” shape and their chemicalcompositions include aluminum up to 0.4% (weight by weight), both ofwhich are unique to this production method. SEM photographs ofrepresentative nano metal particles are shown in FIGS. 2-6. TEMphotographs of a representative composition prepared by dispersing nanometal particles in a liquid carrier are shown in FIGS. 7-8. Thenon-uniform (deformed ellipsoidal) shape of the particles is evidentfrom the XRD data shown in FIG. 9 and from particle size distributionmeasurements.

Useful liquid carriers include water, organic solvents, and combinationsthereof. Useful additives include surfactants, wetting agents,stabilizers, humectants, rheology adjusting agents, adhesion promoters,and the like. Specific examples, many of which are commerciallyavailable, include the following:

-   -   Organic solvents: DPM (di(propyleneglycol)methyl ether), PMA        (1,2-propanediol monomethyl ether acetate), Dowanol DB        (diethylene glycol monobutyl ether), BEA (butoxyethyl acetate).    -   Dispersing agents and stabilizers for solvent-based dispersions:        BYK-9077, Disperbyk-163, PVP K-15.    -   Dispersing/wetting agents and stabilizers for water-based        dispersions: BYK-154, BYK-162, BYK-180, BYK-181, BYK-190,        BYK-192, BYK-333, BYK-348, Tamol T1124, SDS, AOT, Tween 20,        Tween 80, L-77, Betaine, Sodium Laureth Sulfosuccianate and        Sulfate, Tego 735W, Tego 740W, Tego 750W, Disperbyk, PDAC        (poly(diallyldimethylammonium chloride)), Nonidet, CTAC, Daxad        17 and 19 (sodium salt of naphthalene sulfonate formaldehyde        condensate), BASF 104, Solspers 43000, Solspers 44000, Atlox        4913, PVP K-30, PVP K-15, Joncryl 537, Joncryl 8003, Ufoxan,        STPP, CMC, Morwet, LABS W-100A, Tamol 1124.    -   Humectants for water-based dispersions: PMA, DPM, glycerol,        Sulfolam, diethylene glycol, triethanolamine, Dowanol DB,        ethanol, DMF (dimethyl formamide), isopropanol, n-propanol, PM        (1-methoxy-2-propanol), Diglyme (di(ethylene glycol)diethyl        ether), NMP (1-methyl pyrrolidinone).

The printed patterns produced hereby can be treated post printing in anysuitable way to increase their conductivity. The treatments may be anyof the following methods or combinations thereof: methods described inPCT applications WO 2004/005413 A1 (“Low Sintering TemperaturesConductive Inks—a Nano Technology Method for Producing Same”) andWO03/106573 (“A Method for the Production of Conductive and TransparentNano-Coatings and Nano-Inks and Nano-Powder Coatings and Inks ProducedThereby”), application of radiation, microwave, light, flash light,laser sintering, applying pressure, rubbing, friction sintering, thermalheat (applied in any form, e.g. forced air oven, hot plate, etc),continuous radiation, scanned beam, pulsed beam, etc. Preferably thetreatment is a “chemical sintering method” (CSM) described in aprovisional patent application No. ______ entitled “Low TemperatureSintering Process for Preparing Conductive Printed Patterns onSubstrates, and Articles Based Thereon” filed concurrently with thepresent application, and in WO 03/106573.

The dispersions and inks may be printed onto a wide range of surfaces,including flexible, rigid, elastic, and ceramic surfaces. Specificexamples include paper, polymer films, textiles, plastics, glass,fabrics, printed circuit boards, epoxy resins, and the like.

The invention will now be described further by way of the followingexamples.

EXAMPLES EXAMPLE 1

A dispersion of 30% by weight of silver nano powder (#471-G51) (preparedas described in U.S. Pat. No. 5,476,535 and PCT application WO2004/000491 A2), 0.7% Disperbyl® 348 (available from BYK-Chemie, WeselGermany), 5.3% BYK® 190 (also available from BYK-Chemie), 0.35% PVP K-30(available from Alfa Aesar—Johnson Matthey), 3.15% DPM (Dipropyleneglycol methyl ether), 25.5% iso-propanol (IPA), and the balance waterwas prepared by mixing the additives with the solvents and water, thenadding the silver nano powder in portions while mixing with a high speedhomogenizer Dispermat (VMA-GETZMANN GMBH) at 4000 rpm with a 47 mmdiameter dissolver shaft, until the minimum particle size distribution(PSD) was achieved. Typically, homogenization was performed for 10 minat 6000 rpm. The dispersion was printed in a Hewlett-Packard Deskjet 690printer.

EXAMPLE 2

A dispersion of 40% by weight of silver nano powder (#471-W51) (preparedas described in Example 28), 0.6% Disperbyk® 348 (available fromBYK-Chemie, Wesel Germany), 4.6% BYK® 190 (also available fromBYK-Chemie), 0.1% PVP K-30 (available from Alfa Aesar—Johnson Matthey),11% NMP, 0.5% AMP, and the balance water was prepared by mixing theadditives with the solvents and water, then adding the silver nanopowder in portions while mixing with a high speed homogenizer Dispermat(VMA-GETZMANN GMBH) at 4000 rpm with a 47 mm diameter dissolver shaft,until the minimum PSD was achieved. Typically, homogenization wasperformed for 10 min at 6000 rpm. The dispersion was printed in aHewlett-Packard Deskjet 690 printer.

EXAMPLE 3

A dispersion of 50% by weight of silver nano powder (#471-G51) (preparedas described in U.S. Pat. No. 5,476,535 and PCT application WO2004/000491 A2), 0.5% Disperbyk® 348 (available from BYK-Chemie, WeselGermany), 3.8% BYK® 190 (also available from BYK-Chemie), 0.25% PVP K-30(available from Alfa Aesar—Johnson Matthey), 0.25% Tween 20 (availablefrom Aldrich), 9.1% NMP, and the balance water was prepared by mixingthe additives with the solvents and water, then adding the silver nanopowder in portions while mixing with a high speed homogenizer Dispermat(VMA-GETZMANN GMBH) at 4000 rpm with a 47 mm diameter dissolver shaft,until the minimum PSD was achieved. Typically, homogenization wasperformed for 10 min at 6000 rpm. The dispersion was printed in aHewlett-Packard Deskjet 690 printer.

EXAMPLE 4

A dispersion of 60% by weight of silver nano powder (#471-G51) (preparedas described in U.S. Pat. No. 5,476,535 and PCT application WO2004/000491 A2), 0.4% Disperbyk® 348 (available from BYK-Chemie, WeselGermany), 3% BYK® 190 (also available from BYK-Chemie), 0.1% PVP K-30(available from Alfa Aesar—Johnson Matthey), 7.3% NMP, 0.4% AMP, and thebalance water was prepared by mixing the additives with the solvents andwater, then adding the silver nano powder in portions while mixing witha high speed homogenizer Dispermat (VMA-GETZMANN GMBH) at 4000 rpm witha 47 mm diameter dissolver shaft, until the minimum PSD was achieved.The dispersion was printed in a Hewlett-Packard Deskjet 690 printer.

EXAMPLE 5

A dispersion of 60% by weight of silver nano powder (#473-G51) (preparedas described in Example 26), 0.4% Disperbyk® 348 (available fromBYK-Chemie, Wesel Germany), 3% BYK® 190 (also available fromBYK-Chemie), 0.1% PVP K-30 (available from Alfa Aesar—Johnson Matthe),0.4% AMP, 7.3% iso-propanol (IPA), and the balance water was prepared bymixing the additives with the solvents and water, then adding the silvernano powder in portions while mixing with a high speed homogenizerDispermat (VMA-GETZMANN GMBH) at 4000 with a 47 mm diameter dissolvershaft, until the minimum PSD was achieved. Typically, homogenization wasperformed for 10 min. The dispersion was printed in a Hewlett-PackardDeskjet 690 printer.

EXAMPLE 6

A dispersion of 60% by weight of silver nano powder (#473-W51) (preparedas described in patent U.S. Pat. No. 5,476,535 and PCT application WO2004/000491 A2), 0.4% Disperbyk® 348 (available from BYK-Chemie, WeselGermany), 3% BYK® 190 (also available from BYK-Chemie), 0.1% PVP K-30(available from Alfa Aesar—Johnson Matthey), 0.4% AMP, 11% NMP, and thebalance water was prepared by mixing the additives with the solvents andwater, then adding the silver powder in portions while mixing with ahigh speed homogenizer Dispermat (VMA-GETZMANN GMBH) with a 47 mmdiameter dissolver shaft, until the minimum PSD was achieved. Typically,homogenization was performed for 10 min at 6000 rpm. The dispersion wasprinted in a Hewkett-Packard Deskjet 690 printer.

EXAMPLE 7

A dispersion of 10% by weight of silver nano powder (#471-W51) (preparedas described in Example 28), 0.5% Disperbyk® 163 (available fiomBYK-Chemie, Wesel Germany), 0.007% BYK® 333 (also available fromBYK-Chemie), and the balance BEA (Buthoxy ethylacetate) was prepared bymixing the additives with the solvents, then adding the silvernanopowder in portions while mixing with a high speed homogenizerDispermat (VMA-GETZMANN GMBH) at 4000 rpm with a 47 mm diameterdissolver shaft, until the minimum PSD was achieved (D100 76 nm).Typically, homogenization was performed for 10 min at 6000 rpm. Asurface tension of 26 mN/m was measured according to the Dunoy ringmethod.

EXAMPLE 8

A dispersion of 60% by weight of silver nano powder (#473-G51) (preparedas described in Example 26), 3% Disperbyk 163 (available fromBYK-Chemie, Wesel Germany), 0.04% BYK® 333 (also available fromBYK-Chemie), and the balance BEA (Buthoxy ethylacetate) was prepared bymixing the additives with the solvents, then adding the silver nanopowder in portions while mixing with a high speed Premier MillLaboratory Dispersator Series 2000 Model 90 (Premier Mill Corp. USA)having a 47 mm diameter dissolver shaft, until the minimum PSD wasachieved (D100 77 nm). Typically, homogenization was performed for 10min at 6000 rpm. The viscosity of the composition was determined to be17 cP using a Brookfield Viscometer. A surface tension of 26.5 mN/m wasmeasured using the Dunoy ring method. A conductive pattern preparedusing the composition was sintered at 300° C. for 30 minutes, afterwhich the resistivity was measured and determined to be 5 μΩcm.

EXAMPLE 9

A dispersion of 10% by weight of silver nano powder (#473-G51) (preparedas described in Example 26), 0.6% Disperbyk® 190 (available fromBYK-Chemie, Wesel Germany), 0.015% BYK® 348 (also available fromBYK-Chemie), 0.015% PVP K-30 (available from Alfa Aesar—JohnsonMatthey), 0.93% NH₃ water solution, 18.66% NMP, and the balance waterwas prepared by mixing the additives with the solvents and water, thenadding the silver nano powder in portions while mixing at 4000 rpm witha high speed Premier Mill Laboratory Dispersator Series 2000 Model 90(Premier Mill Corp. USA) having a 47 mm diameter dissolver shaft, untilthe minimum PSD was achieved (D100 76 nm). Typically, homogenization wasperformed for 10 min at 6000 rpm. The viscosity of the composition wasdetermined to be 4 cP using a Brookfield Viscometer. A surface tensionof 47.5 mN/m was measured using the Dunoy ring method.

EXAMPLE 10

A dispersion of 40% by weight of silver nano powder (#473-G51) (preparedas described in Example 26), 2.4% Disperbyk® 190 (available fromBYK-Chemie, Wesel Germany), 0.06% BYK® 348 (also available fromBYK-Chemie), 0.06% PVP K-30 (available from Alfa Aesar—Johnson Matthey),0.6% NH₃ water solution, 12% NMP, and the balance water was prepared bymixing the additives with the solvents and water, then adding the silvernano powder in portions while mixing at 4000 rpm with a high speedPremier Mill Laboratory Dispersator Series 2000 Model 90 (Premier MillCorp. USA) having a 47 mm diameter dissolver shaft, until the minimumPSD was achieved (D100 77 nm). Typically, homogenization was performedfor 10 min at 6000 rpm. The viscosity of the composition was determinedto be 17 cP using a Brookfield Viscometer. A surface tension of 47.5mN/m was measured using the Dunoy ring method.

EXAMPLE 11

A dispersion of 60% by weight of silver nano powder (#473-G51) (preparedas described in Example 26), 3% Disperbyk® 190 (available fromBYK-Chemie, Wesel Germany), 0.08% BYK® 348 (also available fromBYK-Chemie), 0.2% PVP K-15 (available from Fluka), 0.147% AMP(2-amino-2-methyl-propanol), 7.343% NMP (1-methyl pyrrolidinone), andthe balance water was prepared by mixing the additives with the solventsand water, then adding the silver nano powder in portions while mixingat 4000 rpm with a high speed Premier Mill Laboratory Dispersator Series2000 Model 90 (Premier Mill Corp. USA) having a 47 mm diameter dissolvershaft, until the minimum PSD was achieved (D100 77 nm). Typically,homogenization was performed for 10 min at 6000 rpm. The viscosity ofthe composition was determined to be 15 cP using a BrookfieldViscometer. A surface tension of 47.5 mN/m was measured using the Dunoyring method.

EXAMPLE 12

A dispersion of 10% by weight of silver nano powder (#471-W51) (preparedas described in Example 28), 1.14% Disperbyk® 190 (available fromBYK-Chemie, Wesel Germany), 0.15% Tween 20 (available from Aldrich),0.15% NH₃ water solution, 1.5% PMA, and the balance water was preparedby mixing the additives with the solvents and water, then adding thesilver nano powder in portions while mixing at 4000 rpm with a highspeed Premier Mill Laboratory Dispersator Series 2000 Model 90 (PremierMill Corp. USA) having a 47 mm diameter dissolver shaft, until theminimum PSD was achieved (D50 50 nm). Typically, homogenization wasperformed for 10 min at 6000 rpm. The viscosity of the composition wasdetermined to be 3 cP using a Brookfield Viscometer. A conductivepattern prepared using the composition was sintered at 300° C. for 30minutes, after which its resistivity was measured and determined to be11 μΩcm.

EXAMPLE 13

A dispersion of 60% by weight of silver nano powder (#471-W51) (preparedas described in Example 28), 3% Disperbyl(® 190 (available fromBYK-Chemie, Wesel Germany), 0.08% BYK® 348 (also available fromBYK-Chemie), 0.2% PVP K-30 (available from Alfa Aesar—Johnson Matthey),0.147% AMP, 7.343% NMP, and the balance water was prepared by mixing theadditives with the solvents and water, then adding the silver nanopowder in portions while mixing at 4000 rpm with a high speed PremierMill Laboratory Dispersator Series 2000 Model 90 (Premier Mill Corp.USA) having a 47 mm diameter dissolver shaft, until the minimum PSD wasachieved (D50 50 nm). Typically, homogenization was performed for 10min. The viscosity of the composition was determined to be 18 cP using aBrookfield Viscometer. A conductive pattern prepared using thecomposition was sintered at 300° C. for 30 minutes, after which itsresistivity was measured and determined to be 11 μΩcm.

EXAMPLE 14

A dispersion of 50% by weight of silver nano powder (#471-W51) (preparedas described in Example 28, 0.3% Disperbyk® 348 (available fromBYK-Chemie, Wesel Germany), 0.5% NH₃ water solution, and the balancewater was prepared by mixing the additives with the solvents and water,then adding the silver nano powder in portions while mixing at 4000 rpmwith a high speed Premier Mill Laboratory Dispersator Series 2000 Model90 (Premier Mill Corp. USA) having a 47 mm diameter dissolver shaft,until the minimum PSD was achieved. Typically, homogenization wasperformed for 10 min at 6000 rpm. A conductive pattern prepared usingthe composition was sintered at 300° C. for 30 minutes, after which itsresistivity was measured and determined to be 19 μΩcm.

EXAMPLE 15

A dispersion of 20% by weight of silver nano powder (#473-G51) (preparedas described in Example 26), 1% Disperbyl(® 190 (available fromBYK-Chemie, Wesel Germany), 0.027% BYK® 348 (also available fromBYK-Chemie), 0.067% PVP K-15 (available from Fluka), 0.313% AMP(2-amino-2-methyl-propanol), 15.76% NMP (1-methyl pyrrolidinone), andthe balance water was prepared by mixing the additives with the solventsand water, then adding the silver nano powder in portions while mixingat 4000 rpm with a high speed Premier Mill Laboratory Dispersator Series2000 Model 90 (Premier Mill Corp. USA) having a 47 mm diameter dissolvershaft, until the minimum PSD was achieved (D100 77 nm). Typically,homogenization was performed for 10 min. The viscosity of thecomposition was determined to bet 15 cP using a Brookfield Viscometer. Asurface tension of 47.5 mN/m was measured using the Dunoy ring method. Aconductive pattern was printed with this dispersion using a Lexmarkprinter Z602, cartridge Lexmark Black 17 and 16 in which the black inkhad been replaced with this dispersion. The dispersion was printed on HPphotoquality paper semi-glossy (C6984A). Two passes were performed. Theconductive pattern was sintered at 150° C. for 90 minutes, after whichits resistivity was measured and determined to be 70 μΩcm.

EXAMPLE 16

The procedure of Example 15 was followed except that the dispersion wasprinted on Epson premium Glossy Photo paper (S0412870). The conductivepattern was sintered at 80° C. for 30 minutes, after which itsresistivity was measured and determined to be 70 μΩcm.

EXAMPLE 17

The procedure of Example 15 was followed except that the composition wasprinted on an HP Premium Inkjet Transparency Film (C3835A). Theconductive pattern was sintered at 150° C. for 30 minutes, after whichits resistivity was measured and determined to be 70 μΩcm.

EXAMPLE 18

A dispersion of 20% by weight of silver palladium nano powder (#455)(prepared as described in patent U.S. Pat. No. 5,476,535 and PCTapplication WO 2004/000491 A2), 4% Disperbyk® 163 (available fromBYK-Chemie, Wesel Germany), and the balance BEA was prepared by mixingthe additives with the solvent, then adding the silver palladium nanopowder in portions while mixing at 4000 rpm with a high speed PremierMill Laboratory Dispersator Series 2000 Model 90 (Premier Mill Corp.USA) having a 47 mm diameter dissolver shaft, until the minimum PSD wasachieved (D50 50 nm). Typically, homogenization was performed for 10min. The viscosity of the composition was determined to be 3 cP using aBrookfield Viscometer. A conductive pattern prepared using thecomposition was sintered at 300° C. for 30 minutes, after which itsresistivity was measured and determined to be 113 μΩcm.

EXAMPLE 19

A dispersion of 40% by weight of silver nano powder (#471-W51) (preparedas described in Example 28), 0.3% BYK® 348 (available from BYK-Chemie,Wesel Germany), 0.6% NH₃ water solution, and the balance water wasprepared by mixing the additives with the solvents and water, thenadding the silver nano powder in portions while mixing at 4000 rpm witha high speed Premier Mill Laboratory Dispersator Series 2000 Model 90(Premier Mill Corp. USA) having a 47 mm diameter dissolver shaft, untilthe minimum PSD was achieved (D100 77 nm). Typically, homogenization wasperformed for 10 min at 6000 rpm. The viscosity of the composition wasdetermined to be 20 cP using a Brookfield Viscometer with a constantshear cone spindle #4 at 200 rpm. A surface tension of 47.5 mN/m wasmeasured using the Dunoy ring method. A conductive pattern preparedusing the composition was sintered at 300° C. for 30 minutes, afterwhich its resistivity was measured and determined to be 17 μΩcm.

EXAMPLE 20

A dispersion of 60% by weight of silver nano powder (#471-W51) (preparedas described in Example 28), 0.3% BYK® 348 (available from BYK-Chemie,Wesel Germany), 0.4% NH₃ water solution, and the balance water wasprepared by mixing the additives with the solvents and water, thenadding the silver nano powder in portions while mixing at 4000 rpm witha high speed Premier Mill Laboratory Dispersator Series 2000 Model 90(Premier Mill Corp. USA) having a 47 mm diameter dissolver shaft, untilthe minimum PSD was achieved (D100 77 nm). Typically, homogenization wasperformed for 10 min at 6000 rpm. The viscosity of the composition wasdetermined to be 78 cP using a Brookfield Viscometer with a constantshear cone, spindle #4 at 200 rpm. A surface tension of 47.5 mN/m wasmeasured using the Dunoy ring method. A conductive pattern preparedusing the composition was sintered at 300° C. for 30 minutes, afterwhich its resistivity was measured and determined to be 24 μΩcm.

EXAMPLE 21

A dispersion of 40% by weight of silver nano powder (#471-W51) (preparedas described in Example 28), 0.3% BYK® 348 (available from BYK-Chemie,Wesel Germany), 0.6% NH₃ water solution, and the balance water wasprepared by mixing the additives with the solvents and water, thenadding the silver powder in portions while mixing at 4000 rpm with ahigh speed Premier Mill Laboratory Dispersator Series 2000 Model 90(Premier Mill Corp. USA) having a 47 mm diameter dissolver shaft, untilthe minimum PSD was achieved (D100 77 nm). Typically, homogenization wasperformed for 10 min at 6000 rpm. The viscosity of the composition wasdetermined to be 20 cP using a Brookfield Viscometer with a constantshear cone spindle #4 at 200 rpm. A surface tension of 47.5 mN/m wasmeasured using the Dunoy ring method. A conductive pattern preparedusing the composition was sintered at 300° C. for 30 minutes, afterwhich its resistivity was measured and determined to be 17 μΩcm.

EXAMPLE 22

A dispersion of 40% by weight of silver nano powder (#471-W51) (preparedas described in Example 28), 2% BYK(® 9077 (available from BYK-Chemie,Wesel Germany), and the balance PMA was prepared by mixing the additivewith the solvent, then adding the silver nano powder in portions whilemixing at 4000 rpm with a high speed Premier Mill Laboratory DispersatorSeries 2000 Model 90 (Premier Mill Corp. USA) having a 47 mm diameterdissolver shaft, until the minimum PSD was achieved (D100 77 nm).Typically, homogenization was performed for 10 min at 6000 rpm. Theviscosity of the composition was determined to be 20 cP using aBrookfield Viscometer with a constant shear cone spindle #4 at 200 rpm.A conductive pattern prepared using the composition was sintered at 300°C. for 30 minutes, after which its resistivity was measured anddetermined to be 17 μΩcm.

EXAMPLE 23

A dispersion of 50% by weight of silver nano powder (#471-W51) (preparedas described in Example 28), 2.5% BYK® 9077 (available from BYK-Chemie,Wesel Germany), and the balance PMA was prepared by mixing the additivewith the solvent, then adding the silver nano powder in portions whilemixing at 4000 rpm with a high speed Premier Mill Laboratory DispersatorSeries 2000 Model 90 (Premier Mill Corp. USA) having a 47 mm diameterdissolver shaft, until the minimum PSD was achieved (D100 77 nm).Typically, homogenization was performed for 10 min at 6000 rpm. Theviscosity of the composition was determined to be 24 cP using aBrookfield Viscometerwith a constant shear cone spindle #4 at 200 rpm. Aconductive pattern prepared using the composition was sintered at 300°C. for 30 minutes, after which its resistivity was measured anddetermined to be 14 μΩcm.

EXAMPLE 24

A dispersion of 60% by weight of silver nano powder (#471-W51) (preparedas described in Example 28), 3% BYK® 9077 (available from BYK-Chemie,Wesel Germany), and the balance PMA was prepared by mixing the additivewith the solvent, then adding the silver nano powder in portions whilemixing at 4000 rpm with a high speed Premier Mill Laboratory DispersatorSeries 2000 Model 90 (Premier Mill Corp. USA) having a 47 mm diameterdissolver shaft, until the minimum PSD was achieved (D100 77 nm).Typically, homogenization was performed for 10 min at 6000 rpm. Theviscosity of the composition was determined to be 40 cP using aBrookfield Viscometer with a constant shear cone spindle #4 at 200 rpm.A conductive pattern prepared using the composition was sintered at 300°C. for 30 minutes, after which its resistivity was measured anddetermined to be 14 μΩcm.

Examples 25-28 describe the preparation of various nano metal powders.

EXAMPLE 25 Nano Powder production through MCP Process #440

Silver nano powder was prepared by making a melt of 30% by weight ofsilver and 70% aluminum (e.g., 300 grams silver and 700 grams aluminum)in a stirred graphite crucible in an induction melting furnace under airat a temperature of at least 661° C. The melt was poured into a 14 mmthick mold made from steel. The molded ingot was left to cool at roomtemperature, and then annealed in an electrical furnace at 400° C. for 2hours. The annealed ingot was left to cool at room temperature, thenrolled at room temperature in a rolling machine (from 13 mm thickness to1 mm thickness in 22 passes). The sheets were cut and heat treated in anelectrical furnace at 560° C. for 4 hours. The heated sheets werequenched in water at room temperature. The sheets were then leached inan excess of a NaOH solution (25% by weight in deionized water—density1.28 grams/ml at room temperature, 1.92 kg NaOH solution per 0.1 kgalloy) at a starting temperature of 28° C. and while cooling to keeptemperature below 70° C. for 12 hours (leaching reactor without externalagitation).

Next, the NaOH solution was decanted and a new portion of 25% NaOHsolution was added (40 gram per 0.1 kg starting alloy), after which thesample was left for 2 hours. The slurry was filtered and washed withdeionized water to a pH of 7. The powder was then dried in an airconvection oven at a temperature below 45° C. The powder produced atthis stage had a prime particle size below 80 nm, as measured by XRD andSEM, and a typical chemical composition of 99.7% silver, 0.3% aluminum,and traces of sodium, iron, copper and other impurities.

An ethanol solution was prepared by dissolving 15.66 grams Span 20 and2.35 grams hexadecanol in 750 ml ethanol. 500 grams of leached drypowder was added to the ethanolic solution and stirred for 2 hours. Theslurry was poured into a tray and the ethanol evaporated at temperaturebelow 45° C. The coated powder was then passed through a jet mill to geta de-agglomerated silver nano powder with particle size (D90) below 80nm, as measured by laser diffraction.

EXAMPLE 26 Nano Powder Production through MCP Process #473-G51

Silver nano powder was prepared by making a melt of 24.4% by weight ofsilver, 0.6% by weight copper and 75% aluminum (e.g., 243.8 gramssilver, 6.3 gram copper and 750 grams aluminum) in a stirred graphitecrucible under air at a temperature of at least 661° C. The melt waspoured into a 14 mm thick mold made from steel. The molded ingot wasleft to cool at room temperature, and then annealed in an electricalfurnace at 400° C. for 2 hours. The annealed ingot was left to cool atroom temperature, and then rolled at room temperature in a rollingmachine (from 13 mm thickness to 1 mm thickness in 24 passes). Thesheets were cut and heat treated in in an electrical furnace at 440° C.for 4 hours. The heated sheets were quenched in water at roomtemperature. The sheets were then leached in an excess of a NaOHsolution (25% by weight in deionized water—density 1.28 grams/ml at roomtemperature, 1.92 kg NaOH solution per 0.1 kg alloy) at a startingtemperature of 28° C. and while cooling to keep the temperature below70° C. for 12 hours (leaching reactor without external agitation).

The NaOH solution was then decanted and a new portion of 25% NaOHsolution was added (40 gram per 0.1 kg starting alloy) and left for 2hours. The powder produced at this stage had a prime particle size below80 nm, as measured by XRD and SEM, and a surface area greater than 5mt²/gram. An ethanol solution was prepared by dissolving 15.66 gramsSpan 20 and 2.35 grams hexadecanol in 750 ml ethanol. 500 grams ofleached dry powder was added to the ethanolic solution and stirred for 2hours. The slurry was poured into a tray and the ethanol evaporated at atemperature below 45° C. The coated powder was then passed through a jetmill to get a de-agglomerated silver nano powder with particle size(D90) below 80 nm, as measured by laser diffraction.

The powder produced in the previous steps was further washed with hotethanol several times (between 3 and 5 times), and then dried in trayuntil all the ethanol evaporated at a temperature below 45° C. Ade-agglomerated silver nano powder with particle size (D90) below 80 nm,as measured by laser diffraction, and organic coating of less than 1.2%by weight, as measured by TGA, was obtained.

EXAMPLE 27 Nano Powder Production through MCP Process #473-SH

Silver nano powder was prepared by making a melt of 24.4% by weight ofsilver, 0.6% by weight copper and 75% aluminum (e.g., 243.8 gramssilver, 6.3 gram copper and 750 grams aluminum) in a stirred graphitecrucible under air at a temperature of at least 661° C. The melt waspoured into a 14 mm thick mold made from steel. The molded ingot wasleft to cool at room temperature, and then annealed in an electricalfurnace at 400° C. for 2 hours. The annealed ingot was left to cool atroom temperature, ands then rolled at room temperature in a rollingmachine (from 13 mm thickness to 1 mm thickness in 24 passes). Thesheets were cut and heat treated in in an electrical furnace at 440° C.for 4 hours. The heated sheets were quenched in water at roomtemperature. The sheets were then leached in an excess of a NaOHsolution (25% by weight in deionized water—density 1.28 grams/ml at roomtemperature, 1.92 kg NaOH solution per 0.1 kg alloy) at a startingtemperature of 28° C., while cooling to keep temperature below 70° C.,for 12 hours (leaching reactor without external agitation).

The NaOH solution was then decanted and a new portion of 25% NaOHsolution was added (40gram per 0.1 kg starting alloy) and left for 2hours. The powder produced at this stage had a prime particle size below80 nm, as measured by XRD and SEM, and surface area greater than 5mt²/gram. An ethanol solution was prepared by dissolving 15.66 gramsSpan 20 and 2.35 grams hexadecanol in 750 ml ethanol. 500 grams ofleached dry powder was added to the ethanolic solution and stirred for 2hours. The slurry was poured into a tray and the ethanol evaporated attemperature below 45° C. The coated powder was passed through a jet millto get a de-agglomerated silver nano powder with particle size (D90)below 80 nm, as measured by laser diffraction.

EXAMPLE 28 Nano Powder Production through MCP Process #471-W51

Silver nano powder was prepared by making a melt of 10% by weight ofsilver, 0.1% by weight copper and 89.9% aluminum (e.g., 99 grams silver,1 gram copper and 899 grams aluminum) in a stirred graphite crucibleunder air at a temperature of at least 661° C. The melt was poured intoa 14 mm thick mold made from steel. The molded ingot was left to cool atroom temperature, and then annealed in an electrical furnace at 400° C.for 2 hours. The annealed ingot was left to cool at room temperature,and then rolled at room temperature in a rolling machine (from 13 mmthickness to 1 mm thickness in 24 passes). The sheets were cut and heattreated in in an electrical furnace at 440° C. for 4 hours. The heatedsheets were quenched in water at room temperature. The sheets wereleached in a NaOH solution (25% by weight in deionized water—density1.28 grams/ml at room temperature, 1.92 kg NaOH solution per 0.1 kgalloy) at a starting temperature of 28° C. while cooling to keeptemperature below 95° C. When the temperature reached 95° C., thesolution was allowed to sit for 10 minutes, after which the NaOHsolution was decanted (leaching reactor without external agitation). Thepowder produced at this stage had a prime particle size below 80 nm, asmeasured by XRD and SEM, and a surface area greater than 11 mt²/gram.

A water solution was prepared by dissolving 13.5 grams Tamol T1124(available from Rohm & Hass) in 170 ml water. 300 grams of leached drypowder was added to the water solution and stirred for 100 minutes. Theslurry was then poured into a tray and the water evaporated attemperature below 45° C. The coated powder was passed through a jet millto get a de-agglomerated silver nano powder with particle size (D90)below 70 nm, as measured by laser diffraction.

EXAMPLE 29 Stability

The composition prepared in Example 15 was filtered after 14 daysthrough a 5 μm filter. The metal load before and after filtration was19.7% and 19.6%, respectively, measured by weight using the TGA method.The PSD was also measured and no change found. This indicates that thecomposition exhibited good stability and dispersability.

EXAMPLES 30-34

Examples 30-34 describe various solvent-based compositions. Theconstituents and properties of the individual compositions are listed inTable 1. The compositions, each of which included 60% by weight ofsilver nano powder No. 471-W51 (prepared as described in Example 28),were prepared as follows: 6 g of liquid carrier having the compositionset forth in Table 1 was homogenized using a Dispermat (VMA-GETZMANNGMBH) at 4000 rpm. 9 g of silver/copper alloy nano powder was addedgradually and then homogenization was performed for 10 min at 6000 rpm.The particle size measurements were measured with the use of HPPS(Malvern Instruments) for dispersions diluted in a liquid similar tothat of the dispersion. The measurements were carried out only forliquid-phase dispersions. Some dispersions formed pastes afterhomogenization; these pastes were not further studied.

TABLE 1 Solvent-based formulations Viscosity Viscosity Surface tensionof Surface tension Example Formulations 25° C. 45° C. Size dispersionSolution of solution 30 60% 471-W51 in (7.6% Byk   14 cp   11 cp 35 nm(9%) 25.45 (mN/m) (0.1% Byk 333 + 24.4 (mN/m) 9077 in PMA) + 0.1% Byk333 235 nm (63%) 7.6% Byk 9077) in 450 nm (27%) PMA 31 60% 471-W51 in(7.6% Byk   18 cp 11.3 cp 15 nm (20%) 25.21 (mN/m) (0.1% Byk 333 + 24.5(mN/m) 163 + 0.1% Byk 333) in 230 nm (80%) 7.6% Byk 163) in (DowanolDB + (Dowanol DB + 30% 30% PMA) PMA) 32 60% 471-W51 in (7.6% Byk 163 7.5 cp  5.1 cp 25 nm (75%) +0.1% Byk 333 (0.1% Byk 333 + 25.3 (mN/m) inBEA) 230 nm (24%) 26.2 mN/m 7.6% Byk 163) in BEA 33 60% Ag (Sp.ol) in(7.6% Byk 12.4 cp  8.8 cp 550 nm (55%) and 26.9 mN/m 7.6% Byk 163 in27.1 (mN/m) 163 in BEA) 1μ(44%). BEA Pecipitation in cuvette during sizemeasurement 34 60% 471-W51 in (7.6% Byk 16.8 cp 11.3 cp 70 nm (8%) 163 +0.1% Byk 333 + 0.5% 230 nm (90%) PVP K-15) in (Dowanol DB + Sometimessmall 30% MPA) peaks at 1μ and 2.7μ are observed

As shown in Table 1, formulations composed of Ag/Cu alloy nano powderdispersed in PMA, Dowanol DB plus PMA, or BEA, and containing BYK 9077or Disperbyk 163 as dispersing agents, and BYK-333 as a wetting agent,are good candidates to be used as ink-jet inks. These formulations arecharacterized by 2-3 peaks in size distribution graphs (15-35 nm,230-235 nm, and 450 nm). Viscosity was found to be in the range 14-18 cPat 25° C. and 11 cP at 45° C., surface tension is about 24-25 mN/m.After about 10 days, there was some sedimentation (easily redispersed byshaking), but there was no clear visible separation, which indicatesthat there were many small particles still dispersed in the liquid.

EXAMPLES 35-43

Examples 35-43 describe various water-based compositions. Theconstituents and properties of the individual compositions are listed inTable 2. The compositions, each of which included 60% by weight ofsilver nano powder No. 473-G51 (prepared as described in Example 26),were prepared as follows: 6 g of liquid carrier having the compositionset forth in Table 2 was homogenized using a Dispermat (VMA-GETZMANNGMBH) at 4000 rpm. 9 g of silver nano powder was added gradually andthen homogenization was performed for 10 min at 6000 rpm. The particlesize measurements were measured with the use of HPPS (MalvernInstruments) for dispersions diluted in a liquid similar to that of thedispersion. The measurements were carried out only for liquid-phasedispersions. Some of the dispersions formed pastes after homogenization;these pastes were not further studied.

TABLE 2 Water-based formulations with NanoPowder product 473-G51Rheological Viscosity Example Sample Dispersants, wetting agents andsolvents Size by volume distribution properties 25° C. 45° C. 35 473-G51(0.2% Byk 348 + 7.6% Byk 190 + 20 nm (90%); 230 nm (8%); sometimesLiquid with a small 0.5% PVP K-30) in [1% AMP in H₂O small peak at 2.7μis observed amount of precipitate (pH = 11.5) + 20% NMP] 36 473-G51(0.2% Byk 348 + 7.6% Byk 190 + 16 nm (80%); 230 nm (11%); small Liquidwith 0.5% PVP K-30) in [1% AMP in H₂O peaks at 1μ and 2.7μ are observedprecipitate (pH = 11.5) + 10% PMA] 37 473-G51 (0.2% Tween 20 + 7.6% Byk190 + 19 nm (30%); 230 nm (7%); Sometimes Liquid with 0.5% PVP K-30) in[1% AMP in H₂O small peaks at 1μ and are 2.7μ precipitate (pH = 11.5) +10% Dowanol DB] 38 473-G51 (0.2% Byk 348 + 7.6% Daxad 19) Paste in [1%AMP in H₂O (pH = 11.5) + 20% NMP] 39 473-G51 (0.2% Byk 348 + 7.6% Byk190 + 20 nm (80%); 230 nm (9%); small Liquid with soft 27.3 cp   26 cp0.5% PVP K-30) in [1% AMP peaks at 1μ; 2.7μ precipitate (pH = 11.5) +20% n-propanol] 40 473-G51 (0.2% Byk 348 + 7.6% Byk 190 + 24 nm (86%);230 nm (13%) Liquid with a small 0.5% PVP K-30) in [1% AMP in H₂O amountof precipitate (pH = 11.5) + 30% NMP] 41 473-G51 (0.2% Byk 348 + 7.6%Byk 190 + 20 nm (70%); 230 nm (29%) Liquid with a small 8.2 cp 6.5 cp0.5% PVP K-15) in [0.5% AMP in H₂O amount of precipitate (pH = 10.9) +20% NMP] 42 473-G51 (0.2% Byk 348 + 7.6% Byk 190 + 25 nm (82%); 230 nm(17%) Liquid with a a small 7.2 cp 5.0 cp 1.0% PVP K-15) in [0.5% AMP inH₂O amount of precipitate (pH = 10.9) + 20% NMP] 43 473-G51 (0.1% Byk333 + 7.6% Byk 163) in There are big peaks at 1μ and 2.7μ Liquid with(Dowanol DB + 30% PMA) precipitate

The results shown in Table 2 demonstrate that useful water-based inkformulations could be prepared using silver nano powder 473-G51. Thispowder was obtained in the presence of Span in hexadecanol followed bywashing by ethanol up to practically exhaustive elimination of organicsubstances. BYK 190 (in combination with wetting agent BYK 348) wasfound to be a useful dispersing agent for this nano powder incombination with PVP K-15 and K-30. In addition, NMP, PMA, Dowanol DBand n-propanol, were used as co-solvents and humectants.

The pH of the compositions was adjusted by AMP(2-amino-2-methyl-propanol). Several experiments were carried out with1% AMP in water (pH 11.5). Dispersions were characterized by sizedistribution containing usually 4 peaks (about 20 nm, 230 nm, and 2 weakpeaks at 1 μm and 2.7 μm). A decrease in AMP concentration to 0.5%resulted in a decrease in pH value to 10.9. Such a correction of pHresulted in an improvement of the dispersion characteristics.

As seen from Table 2, Examples 41 and 42 are characterized by only twopeaks in the size distribution graph: 20-25 nm (70-86%) and 230 nm(13-29%). These formulations exhibited particularly useful viscositiesfor ink jet printing.

EXAMPLES 44-145

Examples 44-145 describe additional water-based compositions. Theconstituents and properties of the individual compositions are listed inTable 3. The compositions, each of which, except as noted, included 60%by weight of silver nano powder No. 471-W51 (prepared as described inExample 28), were prepared as follows: 6 g of liquid carrier having thecomposition set forth in Table 3 was homogenized using a Dispermat(VMA-GETZMANN GMBH) at 4000 rpm. 9 g of silver nano powder was addedgradually and then homogenization was performed for 10 min at 6000 rpm.The particle size measurements were measured with the use of HPPS(Malvern Instruments) for dispersions diluted in a liquid similar tothat of the dispersion. The measurements were carried out only forliquid-phase dispersions. Some of the dispersions formed pastes afterhomogenization; these pastes were not further studied.

TABLE 3 Water-based formulations with NanoPowder product 471-W51 ExampleSample Dispersants, wetting agents and solvents 44 471-W51-Ag/Cu 7.6%Byk 192 in (0.1% alloy stabilized by NH₄OH + 10% DPM) Tamol 1124 45471-W51-Ag/Cu 7.0% T-1124 in (H₂O + 10% DPM) alloy stabilized by Tamol1124 46 471-W51-Ag/Cu 7.0% T 1124 in 1 M NaOH alloy stabilized by Tamol1124 47 471-W51-Ag/Cu 7.6% Byk 192 in (0.1% NH₄OH + 10% alloy stabilizedby PMA) Tamol 1124 48 471-W51-Ag/Cu 10.5% Byk 192 in (0.1% NH₄OH + 10%alloy stabilized by PMA) Tamol 1124 49 471-W51-Ag/Cu 4.5% Byk 192 in(0.1% NH₄OH + 10% alloy stabilized by PMA) Tamol 1124 50 471-W51-Ag/Cu7.6% Byk 190 in (0.1% NH₄OH + 10% alloy stabilized by PMA) Tamol 1124 51471-W51-Ag/Cu 7.6% Betaine in (0.1% NH₄OH + 10% alloy stabilized by PMA)Tamol 1124 52 471-W51-Ag/Cu 1.5% Betaine in (0.1% NH₄OH + 10% alloystabilized by PMA) Tamol 1124 53 471-W51-Ag/Cu 1.5% Sodium LaurethSulfosuccinate in alloy stabilized by (H₂O + 10% PMA) Tamol 1124 54471-W51-Ag/Cu 1.5% Sodium Laureth Sulfate in alloy stabilized by (H₂O +10% PMA) Tamol 1124 55 471-W51-Ag/Cu 7.6% Tego 740w in (H₂O + 10% PMA)alloy stabilized by Tamol 1124 56 471-W51-Ag/Cu 4.5% Tego 740w in (H₂O +10% PMA) alloy stabilized by Tamol 1124 57 471-W51-Ag/Cu 12% Tego 740win (H₂O + 10% PMA) alloy stabilized by Tamol 1124 58 471-W51-Ag/Cu 7.6%Tego 740w in (H₂O + 10% DPM) alloy stabilized by Tamol 1124 59471-W51-Ag/Cu 3% AOT in (H₂O + 10% PMA) alloy stabilized by Tamol 112460 471-W51-Ag/Cu 7.6% Tego 740w in (0.1% alloy stabilized by NH₄OH + 10%PMA) Tamol 1124 61 471-W51-Ag/Cu 7.6% Tego 735w in (H₂O + 10% PMA) alloystabilized by Tamol 1124 62 471-W51-Ag/Cu 45% Byk 190 in (H₂O + 10% PMA)alloy stabilized by Tamol 1124 63 471-W51-Ag/Cu 15% (active) Tego 750win (H₂O + 10% alloy stabilized by PMA) Tamol 1124 64 471-W51-Ag/Cu 7.6%Disperbyk in (H₂O + 10% PMA) alloy stabilized by Tamol 1124 65471-W51-Ag/Cu 0.5% PDAC (Med. M.W.) in (H₂O + 5% alloy stabilized byGlycerol) Tamol 1124 66 471-W51-Ag/Cu 7.6% Tego 740w in (H₂O + 20% PMA)alloy stabilized by Tamol 1124 67 471-W51-Ag/Cu (4.5% Tego 740w + 5%Na-citrate) in alloy stabilized by (H₂O + 10% PMA) Tamol 1124 68471-W51-Ag/Cu 7.6% Dispex A-40 in H₂O alloy stabilized by Tamol 1124 69471-W51-Ag/Cu (1% Byk 333 + 7.6% Byk 190) in alloy stabilized by (H₂O +10% PMA) Tamol 1124 70 471-W51-Ag/Cu (1% Tween 20 + 7.6% Byk 190) inalloy stabilized by (H₂O + 10% PMA) Tamol 1124 71 471-W51-Ag/Cu (1%Tween 20 + 7.6% Byk 190) in alloy stabilized by (H₂O + 15% IPA + 10%PMA) Tamol 1124 72 471-W51-Ag/Cu (1% Tween 20 + 7.6% Byk 190) in alloystabilized by (H₂O + 5% IPA + 10% PMA) Tamol 1124 73 471-W51-Ag/Cu 7.6%Tween 20 in (H₂O + 10% PMA) alloy stabilized by Tamol 1124 74471-W51-Ag/Cu 7.6% Tween 20 in (H₂O + 10% alloy stabilized by Sulfolan)Tamol 1124 75 471-W51-Ag/Cu 7.6% Tween 20 in (H₂O + 10% alloy stabilizedby Diethyleneglycol) Tamol 1124 76 471-W51-Ag/Cu (7.6% Tween 20 + 0.5%NMP) in alloy stabilized by (H₂O + 10% PMA) Tamol 1124 77 471-W51-Ag/Cu(7.6% Tween 20 + 1% PVP K-40) in alloy stabilized by (H₂O + 10% PMA)Tamol 1124 78 471-W51-Ag/Cu (7.6% Tween 20 + 1% Joncryl 537) in alloystabilized by (H₂O + 10% PMA) Tamol 1124 79 471-W51-Ag/Cu (7.6% Tween20 + 1% Joncryl 8003) in alloy stabilized by (H₂O + 10% PMA) Tamol 112480 471-W51-Ag/Cu (7.5% Nonidet in alloy stabilized by(Triethanolamine/H₂O = 1:3) Tamol 1124 81 471-W51-Ag/Cu 3% Nonidet in10% Triethanolamine alloy stabilized by Tamol 1124 82 471-W51-Ag/Cu (1%Tween 20 + 7.6% Byk 190) in H₂O alloy stabilized by Tamol 1124 83471-W51-Ag/Cu (1% Tween 20 + 7.6% Byk 190) in H₂O alloy stabilized byTamol 1124 84 471-W51-Ag/Cu (1% Tween 20 + 7.6% Byk 190 + 0.5% alloystabilized by Byk 348) in (H₂O + 10% PMA) Tamol 1124 85 471-W51-Ag/Cu(0.2% Tween 20 + 7.6% Byk 190) in alloy stabilized by (H₂O + 10% PMA)Tamol 1124 86 471-W51-Ag/Cu 7.6% Byk 190 in (H₂O + 10% PMA) alloystabilized by Tamol 1124 87 471-W51-Ag/Cu 15% Byk 190 in (H₂O + 10% PMA)alloy stabilized by Tamol 1124 88 471-W51-Ag/Cu (0.5% Tween 20 + 7.6%Byk 190) in alloy stabilized by (H₂O + 10% PMA) Tamol 1124 89471-W51-Ag/Cu (1% Tween 20 + 7.6% Byk 190) in alloy stabilized by (H₂O +10% Dowanol DB) Tamol 1124 90 471-W51-Ag/Cu (2.0% Byk 154 + 7.6% Byk181) in alloy stabilized by (H₂O + 10% Ethanol) Tamol 1124 91471-W51-Ag/Cu (1.0% Byk 181 + 7.6% Byk 190) in alloy stabilized by(H₂O + 10% Ethanol) Tamol 1124 92 471-W51-Ag/Cu (1% Urea + 1% Byk 181 +7.6% Byk alloy stabilized by 190) in (H₂O + 10% Ethanol) Tamol 1124 93471-W51-Ag/Cu (1% Byk 181 + 7.6% Byk 190) in alloy stabilized by (H₂O +10% PM) Tamol 1124 94 471-W51-Ag/Cu (1% Byk 181 + 7.6% Byk 154) in alloystabilized by (H₂O + 10% Ethanol) Tamol 1124 95 471-W51-Ag/Cu 7.6% Tween20 in (H₂O + 10% DMF) alloy stabilized by Tamol 1124 96 471-W51-Ag/Cu(1% Byk 181 + 10% Byk 154) in alloy stabilized by (H₂O + 10% Ethanol)Tamol 1124 97 471-W51-Ag/Cu (1% Byk 181 + 7.6% Byk 190) in alloystabilized by (H₂O + 20% Ethanol) Tamol 1124 98 471-W51-Ag/Cu (1% Byk181 + 7.6% Byk 190) in alloy stabilized by (H₂O + 20% DMF) Tamol 1124 99471-W51-Ag/Cu (1% Urea + 1% Tween 20 + 7.6% Byk alloy stabilized by 190)in (H₂O + 10% DMF + 10% Tamol 1124 Ethanol) 100  471-W51-Ag/Cu (1%Urea + 7.6% Tween 20) in alloy stabilized by (H₂O + 10% DMF) Tamol 1124101  471-W51-Ag/Cu (1% Urea + 7.6% Tween 20) in alloy stabilized by(H₂O + 10% DMF + 10% PMA) Tamol 1124 102  471-W51-Ag/Cu (1% Urea + 7.6%Tween 20) in alloy stabilized by (H₂O + 10% DMF + 10% Dow.DB) Tamol 1124103  471-W51-Ag/Cu (1% Urea + 1% Byk 181 + 7.6% Byk alloy stabilized by190) in (H₂O + 10% Tamol 1124 DMF + 10% Dowanol DB) 104  471-W51-Ag/Cu(1% Urea + 1% Byk 181 + 7.6% Byk alloy stabilized by 190) in (H₂O + 10%DMF + 10% PMA) Tamol 1124 105  471-W51-Ag/Cu 7.6% Tween 20 in (H₂O + 20%Ethanol + 10% alloy stabilized by PMA) Tamol 1124 106  471-W51-Ag/Cu7.6% Tween 20 in (H₂O + 20% alloy stabilized by Ethanol + 10% DowanolDB) Tamol 1124 107  471-W51-Ag/Cu (1% Byk 181 + 7.6% Byk 180) in alloystabilized by (H₂O + 10% IPA + 10% Dowanol DB) Tamol 1124 108 471-W51-Ag/Cu 7.6% Tween 20 in H₂O + (1% Span 20 alloy stabilized by in10% IPA + 10% Dowanol DB) Tamol 1124 109  471-W51-Ag/Cu 7.6% Tween 20 in(H₂O + 20% alloy stabilized by IPA + 10% Dowanol DB) Tamol 1124 110 471-W51-Ag/Cu 7.6% Tween 20 in (H₂O + 20% IPA) alloy stabilized by Tamol1124 111  471-W51-Ag/Cu 7.6% Tween 80 in (H₂O + 20% IPA) alloystabilized by Tamol 1124 112  471-W51-Ag/Cu 5% CTAC in (H₂O + 20% IPA)alloy stabilized by Tamol 1124 113  471-W51-Ag/Cu 10% CTAC in (H₂O + 20%IPA) alloy stabilized by Tamol 1124 114  471-W51-Ag/Cu (2% Daxad 19 +7.6% Byk 190) in alloy stabilized by (H₂O + 20% IPA) Tamol 1124 115 471-W51-Ag/Cu alloy (7.6% BasF 104 + 0.025% NH₄OH) in (H₂O + 20%stabilized by Tamol 1124 IPA) 116  471-W51-Ag/Cu alloy (5% BasF 104 +0.025% NH₄OH) in (H₂O + 20% stabilized by Tamol 1124 IPA) 117 471-W51-Ag/Cu alloy (7.6% Tween 20 + 0.025% NH₄OH) in (H₂O + 20%stabilized by Tamol 1124 IPA) 118  471-W51-Ag/Cu alloy (1% Tween 20 +7.6% Bk 190 + 0.1% NH₄OH) in stabilized by Tamol 1124 (H₂O + 20% IPA)119  471-W51-Ag/Cu alloy (1% Tween 20 + 7.6% Bk 190 + 0.1% NH₄OH) instabilized by Tamol 1124 (H₂O + 20% Diglyme) 120  471-W51-Ag/Cu alloy(45% Byk 190 + 1% Tween 20 + 0.1% NH₄OH) in stabilized by Tamol 1124(H₂O + 20% Diglyme) 121  471-W51-Ag/Cu alloy (2% L-77 + 7.6% Byk 190 +0.1% NH₄OH) in stabilized by Tamol 1124 (H₂O + 20% IPA + 10% Dowanol DB)122  471-W51-Ag/Cu alloy (1% Byk 181 + 7.6% Byk 180) in (H₂O + 10%stabilized by Tamol 1124 Diglyme + 10% Dowanol DB) 123  471-W51-Ag/Cualloy (1% L-77 + 7.6% Byk 180) in (H₂O + 20% stabilized by Tamol 1124Dowanol DB) 124  471-W51-Ag/Cu alloy (2% Tween 20 + 7.6% Byk 180 in(H₂O + 20% stabilized by Tamol 1124 Diglyme) 125  471-W51-Ag/Cu alloy(0.5% Tween 20 + 7.6% Byk 180) in (H₂O + 20% stabilized by Tamol 1124Diglyme) 126  471-W51-Ag/Cu alloy (1% Byk 348 + 7.6% Byk 180) in (H₂O +20% stabilized by Tamol 1124 Diglyme) 127  471-W51-Ag/Cu alloy (0.91%Byk 181 + 13.6% Byk 180) in (H₂O + 9.1% stabilized by Tamol 1124Diglyme + 9.1% Dowanol DB) 128  471-W51-Ag/Cu alloy (1% Byk 181 + 5% Byk180) in (H₂O + 10% stabilized by Tamol 1124 Diglyme + 10% Dowanol DB)129  471-W51-Ag/Cu alloy (4% Urea + 1% Byk 181 + 7.6% Byk 180) instabilized by Tamol 1124 (H₂O + 10% Diglyme + 10% Dowanol DB) 130 471-W51-Ag/Cu alloy (0.2% SDS + 1% Byk 181 + 7.6% Byk 180) in stabilizedby Tamol 1124 (H₂O + 10% Diglyme + 10% Dowanol DB) 131  471-W51-Ag/Cualloy (1% Byk 181 + 10% Byk 180) in (H₂O + 10% stabilized by Tamol 1124Diglyme + 10% Dowanol DB) 132  471-W51-Ag/Cu alloy (0.8% PVP K-30 + 0.5%Byk 348 + 7.6% Byk stabilized by Tamol 1124 190 in [0.04% AMP in H₂O(pH= 10) + 40% IPA + 5% DPM) 133  471-W51-Ag/Cu alloy (0.8% PVP K-30 + 0.5%Tween 20 + 0.5% stabilized by Tamol 1124 Byk 348 + 15.2% Solsperse44000) in (0.04% AMP in H₂O(pH = 10) + 40% IPA + 5% DPM) 134 471-W51-Ag/Cu alloy (0.5% Tween 20 + 0.5% Byk 348 + 7.6% stabilized byTamol 1124 Solsperse 43.000 + 0.8% PVP (K-30) in (40% IPA + 5% DPM +0.04% AMP in H₂O (pH = 10)] 135  471-W51-Ag/Cu alloy (0.5% Tween 20 +0.5% Byk 348 + 7.6% Byk stabilized by Tamol 1124 190 + 0.5% PVP K-30) in[0.04% AMP in H₂O (pH = 10) + 20% NMP]] 136  40% 471-W51-Ag/Cu alloy(0.5% Tween 20 + 0.5% Byk 348 + 7.6% Byk stabilized by Tamol 1124 190 +0.5% PVP K-30) in [0.04% AMP in H₂O (pH = 10) + 20% NMP]] 137  40%471-W51-Ag/Cu alloy (0.2 Byk 348 + 7.6% Byk 190 + 0.5% PVP K- stabilizedby Tamol 1124 30) in [1% AMP in H₂O (pH = 11.5) + 20% NMP] 138  40%471-W51-Ag/Cu alloy (0.2 Byk 348 + 7.6% Byk 190 + 0.5% PVP K- stabilizedby Tamol 1124 30) in [1% AMP in H₂O (pH = 11.5) + 20% NMP] 139  60%471-W51-Ag/Cu alloy 0.2% Byk 348 + 7.6% Atlox 4913) in [1% stabilized byTamol 1124 AMP in H₂O (pH = 11.5) + 20% NMP] 140  471-W51-Ag/Cu alloy(0.2 Byk 348 + 7.6% Daxad 19) in [1% AMP stabilized by Tamol 1124 in H₂O(pH = 11.5) + 20% NMP] 141  471-W51-Ag/Cu alloy (0.2 Byk 348 + 5%Solsperse 44000) in [1% stabilized by Tamol 1124 AMP in H₂O (pH =11.5) + 20% NMP] 142  471-W51-Ag/Cu alloy (0.2 Byk 348 + 7.6% Solsperse44000) in [1% stabilized by Tamol 1124 AMP in H₂O (pH = 11.5) + 20% NMP]143  471-W51-Ag/Cu alloy (0.2 Byk 348 + 7.6% Byk 190 + 0.5% PVP K-stabilized by Tamol 1124 30) in [1% AMP in H₂O (pH = 11.5) + 20% n-propanol] 144  471-W51-Ag/Cu alloy (0.2 Byk 348 + 7.6% Byk 190 + 0.5%PVP K- stabilized by Tamol 1124 30) in [1% AMP in H₂O (pH = 11.5) + 30%NMP] 145  471-W51-Ag/Cu alloy (0.2 Byk 348 + 7.6% Byk 190 + 0.5% PVP K-stabilized by Tamol 1124 30) in [1% AMP in H₂O (pH = 11.5) + 20% n-propanol + 10% NMP] Rheological Example Size by volume distributionproperties Viscosity 44 Peaks until 1μ Liquid with precipitate 45 Peaksuntil 2.6μ Liquid with precipitate 46 Peaks until 2.6μ Liquid withprecipitate 47 Peaks until 1μ Liquid with precipitate 48 Peaks until2.7μ Liquid with precipitate 49 Peaks until 2.7μ Liquid with precipitate50 Peaks until 2.7μ Liquid with precipitate 51 Peaks until 1μ Liquidwith precipitate 52 2.5μ Liquid with precipitate 53 1.6μ; 2.5μ Liquidwith precipitate 54 1μ; 1.5μ Liquid with precipitate 55 Peaks until 1μLiquid with 99.6 cp precipitate (25° C.) 56 Peaks until 1μ; small peakLiquid with at 2.7μ precipitate 57 Peaks at 940 nm; 2.7μ Liquid withprecipitate 58 Peaks at 940 nm; 2.7μ Liquid with precipitate 59 2.4μLiquid with precipitate 60 Peaks at 940 nm; 2.7μ Liquid with precipitate61 2.4μ Liquid with precipitate 62 Peaks until 600 nm; small Liquid withpeak at 2μ precipitate 63 Peaks at 940 nm and 2.7μ Liquid withprecipitate 64 Paste 65 Paste 66 Liquid with  185 cp precipitate (25°C.) 67 616 nm (26%); 933 nm Liquid (73%); 2.7μ (2%) with precipitate 68Paste 69 Peak at 2.7μ Liquid with precipitate 70 Peaks until 600 nmLiquid with precipitate 71 Peaks until 600 nm Liquid with precipitate 72Peaks until 600 nm Liquid with precipitate 73 Sometimes a peak at 2.7μLiquid with appears precipitate 74 Peaks until 600 nm, small Liquid withpeak at 2.7μ precipitate 75 Peaks until 600 nm, small Liquid with peakat 2.7μ precipitate 76 Peaks until 600 nm, small Liquid with peak at2.7μ precipitate 77 Peaks until 600 nm, small Liquid with peak at 2.7μprecipitate 78 Sometimes a small peak at Liquid with 2.7μ appearsprecipitate 79 Sometimes there is a small Liquid with peak at 2.7μprecipitate 80 There are peaks at 940 nm; Paste 2.7μ 81 There are peaksat 940 nm; Paste 2.7μ 82 20 nm (37%) 236.2 (2%) Liquid with 33.2 cpprecipitate (25° C.) 83 20 nm (37%) 236.2 (2%) Liquid with 33.2 cpprecipitate (25° C.) 84 There is a peak at 2.7μ Liquid with precipitate85 There is a peak at 2.7μ Liquid with precipitate 86 There are peaks at940 nm Liquid with and 2.7μ precipitate 87 Sometimes a peak at 2.7μLiquid with appears precipitate 88 Sometimes peaks at 940 nm Liquid withand 2.7μ appear precipitate 89 Sometimes peaks at 940 nm Liquid with and2.7μ appear precipitate 90 940 nm; 2.7μ Almost paste 91 18 nm; 220 nmLiquid with precipitate 92 18 nm; 220 nm Liquid with precipitate 93Peaks until 230 nm Liquid with precipitate 94 Peaks at 385, 583.1 nmAlmost paste 95 10-18 nm; 240 nm; 400 nm; Liquid with small peak 2.7μprecipitate 96 500-600 nm Almost paste 97 24 nm; 230 nm; sometimesLiquid with small peak at 2.7μ appears precipitate 98 20 nm; 230 nm;small peak Liquid with at 2.7μ precipitate 99 20-30 nm; 230 nm Liquidwith precipitate 100  17-18 nm; 200 nm; small Liquid with peak at 2.7μprecipitate 101  25 nm; 230 nm; sometimes Liquid with 36.2 cp a smallpeak at 2.7μ precipitate (25° C.) appears  21. cp (45° C.) 102  20 nm;230 nm; sometimes Liquid with 56.4 cp a small peak at 2.7μ precipitate(25° C.) appears  50. cp (45° C.) 103  20 nm; 230 nm; sometimes Liquidwith 34.7 cp a small peak at 2.7μ precipitate (25° C.) appears 19.1 cp(45° C.) 104  20 nm; 230 nm; sometimes Liquid with 56.4 cp a small peakat 2.7μ precipitate (25° C.) appears 25.0 cp (45° C.) 105  20 nm; 230nm; sometimes Liquid with a small peak at 2.7μ precipitate appears 106 20 nm; 230 nm; sometimes Liquid with a small peak at 2.7μ precipitateappears 107  500 nm Almost paste 108  20-30 nm; 230 nm; small Liquidwith peak at 2.7μ appears precipitate 109  230 nm and sometimes a Liquidwith small peak at 2.7μ appears precipitate 110  20 nm; 230 nm Liquidwith precipitate 111  20 nm; 230 nm Liquid with precipitate 112  20 nm;230 nm Paste 113  1μ; 2μ Paste 114  600 nm; 700 nm Liquid withprecipitate 115  20 nm (80%); 230 nm (14%); sometimes a Liquid withsmall peak at 2.7μ appears precipitate 116  10-12 nm (50%); 230 nm (7%);sometimes Liquid with a small peak at 2.7μ appears precipitate 117 10-12 nm (50%); 230 nm (7%); sometimes Liquid with a small peak at 2.7μappears precipitate 118  10-12 nm (50%); 230 nm (7%); sometimes Liquidwith a small peak at 2.7μ appears precipitate 119  10-12 nm (50%); 230nm (7%); sometimes Liquid with a small peak at 2.7μ appears precipitate120  420 nm; 600 nm; 1μ; 2μ Liquid with precipitate 121  49 nm (26%);230 nm (25%); sometimes Liquid with small peaks at 1μ and 2.7μ appearprecipitate 122  450 nm; 600 nm Liquid with precipitate 123  Peaks until1μ Paste 124  8 nm (90%); 200 nm; 400 nm; 600 nm (2-3%) Liquid withprecipitate 125  15 nm (60%); 1μ (33%); 2.7μ Liquid with precipitate126  20 nm (24%); 240 nm (4%); 400 nm (9%); Liquid with 1μ (30%)precipitate 127  400 nm Liquid with precipitate 128  Big peaks at 1μ and2.7μ Liquid with precipitate 129  Big peaks at 1μ and 2.7μ Liquid withprecipitate 130  Big peaks at 1μ Liquid with precipitate 131  Peaks at1μ and 2.7μ Liquid with precipitate 132  20 nm; 230 nm; sometimes a peakat 2.7μ Liquid with appears precipitate 133  Paste 134  Paste 135  20nm; 230 nm; sometimes a small peak at Liquid with 2.7μ appearsprecipitate 136  20 nm; 230 nm; sometimes a small peak at Liquid withsmall 2.7μ appears and soft precipitate 137  20 nm; 230 nm; sometimes asmall peak at Liquid with small 10.9 cp 2.7μ appears and softprecipitate (25° C.) 6.54 138  20 nm; 230 nm; sometimes a small peak atLiquid with small 2.7μ appears and soft precipitate 139  20 nm; 230 nmLiquid with precipitate 140  Paste 141  20 nm; 230 nm; sometimes a smallpeat at Liquid with 2.7μ appears precipitate 142  20 nm; 230 nm;sometimes a small peat at Liquid with 2.7μ appears precipitate 143  20nm; 230 nm (15%); 1μ; 2.7μ Liquid with precipitate 144  20 nm (70%); 230nm (14%); sometimes a Liquid with small peat at 2.7μ appears precipitate145  20 nm (70%); 230 nm (14%); sometimes a Liquid with small peat at2.7μ appears precipitate

The results shown in Table 3 demonstrate that the best dispersions couldbe obtained at high pH values, e.g., about 10. Therefore, experimentswere carried out with the addition of ammonia solution, and then with anorganic amine (AMP) to avoid NH₃ evaporation. Low concentrations of AMPwere used (e.g., 0.04% AMP in water gives pH=10). Because thepreparation of silver nano powder dispersions results in a decrease inpH to 9, the AMP concentration in all experiments was 1%. The bestdispersions (very diluted, without a dispersant or wetting agent) wereobtained with the use of isopropanol and ethanol as humectants; theoptimal concentrations were found to be 40% for both additives. Severalformulations also contained DPM as an additive in order to suppressevaporation.

As seen in Table 3, most of the formulations contained compactprecipitates and had relatively high viscosities. A decrease in silvernano powder concentration from 60% to 40% resulted in a decrease in theamount of precipitate, which also became less compact. Viscosities offormulations containing 40% of silver nano powder (e.g., Examples 137and 138) were 10.9 cP at 25° C. and 6.9 cP at 45° C.

EXAMPLES 146-167

Examples 146-167 describe additional water-based compositions. Theconstituents and properties of the individual compositions are listed inTable 4. The compositions, each of which included 60% by weight ofsilver nano powder No. 1440 (prepared in the presence of Daxad 19stabilizer following the procedures generally described in U.S. Pat. No.5,476,535 and PCT application WO 2004/000491 A2), were prepared asfollows: 6 g of liquid carrier having the composition set forth in Table4 was homogenized using a Dispermat (VMA-GETZMANN GMBH) at 4000 rpm. 9 gof silver nano powder was added gradually and then homogenization wasperformed for 10 min at 6000 rpm. The particle size measurements weremeasured with the use of HPPS (Malvern Instruments) for dispersionsdiluted in a liquid similar to that of the dispersion. The measurementswere carried out only for liquid-phase dispersions. Some of thedispersions formed pastes after homogenization; these pastes were notfurther studied.

TABLE 4 Water-based formulations with NanoPowder product 1440 stabilizedby Daxad 19 Dispersants, wetting agents and Example Sample solvents Sizeby volume distributions Rheological properties Viscosity 146 1440 (LotAS 1015) 2% SDS in (H₂O + 10% PMA) 2.7μ Paste Stabilized by Daxad 19 1471440 (Lot AS 1015) 15% Byk 190 in (0.1% NH₄OH + 10% 935 nm; 2μ Liquidwith precipitate Stabilized by Daxad 19 PMA) 148 1440 (Lot AS 1015) 7.6%Tego 740 W in H₂O 2.7μ Pastse Stabilized by Daxad 19 149 1440 (Lot AS1015) 7.6% Byk 190 in (H₂O + 10% PMA) 248.7 nm (18%); 425.5 nm Liquidwith precipitate 11.3 cp Stabilized by Daxad 19 (56%); 595.1 nm (15%);and (25° C.) small peaks at 940 nm and 2.7μ 10.6 cp (45° C.) 150 1440(Lot AS 1015) 15% Byk 190 in H₂O Peaks until 600μ and a small Liquidwith precipitate Stabilized by Daxad 19 peak at 2.7μ 151 1440 (Lot AS1015) 7.5% Byk 190 in H₂O There are peaks at 940 nm and Liquid withprecipitate Stabilized by Daxad 19 2.7μ 152 1440 (Lot AS 1015) 15% Byk190 in (H₂O + 10% DPM) There are peaks at 940 nm and Liquid withprecipitate Stabilized by Daxad 19 2.7μ 153 1440 (Lot AS 1015) 7.5% Byk190 in (H₂O + 10% DPM) There are peaks at 940 nm and Liquid withprecipitate Stabilized by Daxad 19 2.7μ 154 1440 (Lot AS 1015) 15% Byk190 in (H₂O + 10% PMA) There are peaks at 940 nm and Liquid withprecipitate Stabilized by Daxad 19 2.7μ 155 1440 (Lot AS 1015) 7.6%Dispex A40 in H₂O There are peaks at 940 nm and Liquid with precipitateStabilized by Daxad 19 2.7μ 156 1440 (Lot AS 1015) 7.6% Na-polyacrylicacid 2100 in H₂O There are peaks at 940 nm and Liquid with precipitateStabilized by Daxad 19 2.7μ 157 1440 (Lot AS 1015) (1% Tween 20 + 7.6%Byk 190) in There are peaks at 940 nm and Liquid with precipitateStabilized by Daxad 19 (H₂O + 10% PMA) 2.7μ 158 1440 (Lot AS 1015) 7.6%Tween 20 in (H₂O + 10% Sultolan) Paste Stabilized by Daxad 19 159 1440(Lot AS 1015) 7.6% Tween 20 in (H₂O + 10% PMA) Paste Stabilized by Daxad19 160 1440 (Lot AS 1015) (1% Byk 333 + 7.6% Byk 190) in 940 nm; 2.7μLiquid with precipitate Stabilized by Daxad 19 (H₂O + 10% PMA) 161 1440(Lot AS 1015) (7.6% Byk 190 + 1% PVP K-30) in 940 nm; 2.7μ Liquid withprecipitate Stabilized by Daxad 19 (H₂O + 10% PMA) 162 1440 (Lot AS1015) 3% Nonidet in 10% Triethanolamine 940 nm; 2.7μ Liquid withprecipitate Stabilized by Daxad 19 163 1440 (Lot AS 1037) 7.6% Byk 9077in PMA Peaks until 1μ Liquid with precipitate Stabilized by Daxad 19 1641440 (Lot AS 1037) 7.6% Byk 9076 in PMA Peaks until 1μ Liquid withprecipitate Stabilized by Daxad 19 165 1440 (Lot AS 1037) (1% Byk 181 +7.6% Byk 154) in Paste Stabilized by Daxad 19 (H₂O + 10% Ethanol) 1661440 (Lot AS 1037) 7.6% Tween 20 in (H₂O + 20% DPA) 200 nm; 400 nm; 2.7μLiquid with precipitate Stabilized by Daxad 19 167 1440 (Lot AS 1037)(7.6% Dasad 19 + 0.2% Byk 348) in (1% Paste Stabilized by Daxad 19 AMPin H₂O (pH = 11.5) + 20% NMP)

As shown in Table 4, most of the formulations contained particles with asize of about 1 and 2.7 μm. In addition, each formulation resulted inthe formation of a paste or bulky precipitate.

EXAMPLES 168-172

Examples 168-172 describe additional water and solvent-basedcompositions. The constituents and properties of the individualcompositions are listed in Table 5. The compositions, each of whichincluded 60% by weight of silver nano powder No. 473-SH or 44-052(prepared following the procedures generally described in U.S. Pat. No.5,476,535 and PCT application WO 2004/000491 A2), were prepared asfollows: 6 g of liquid carrier having the composition set forth in Table5 was homogenized using a Dispermat (VMA-GETZMANN GMBH) at 4000 rpm. 9 gof silver nano powder was added gradually and then homogenization wasperformed for 10 min at 6000 rpm. As shown in Table 5, each formulationformed a paste.

TABLE 5 Solvent and water-based formulations with NanoPowder products473-SH and 440-052 Rheological Example Sample Dispersants, wettingagents and solvents properties 168 473-SH (0.1% Byk 333 + 7.6% Byk 163)in (Dowanol Paste (Lot AS 1060) DB + 30% PMA) 169 473-SH (0.2% Byk 348 +7.6% Byk 190 + 0.5% PVP Paste (Lot AS 1060) K-30) in [1% AMP in H₂O (pH= 11.5) + 20% n-propanol] 170 473-SH (0.2% Byk 348 + 7.6% Byk 190 + 0.5%PVP Paste (Lot AS 1060) K-30) in (H₂O + 20% n-propanol) 171 440-052(0.1% Byk 333 + 7.6% Byk 163) in (Dowanol Paste (Lot AS 1055) DB + 30%PMA) 172 440-052 (0.2% Byk 348 + 7.6% Byk 190 + 0.5% PVP Paste (Lot AS1055) K-30) in (H₂O + 20% n-propanol)

EXAMPLES 173-178

The formulations described in Examples 173-178 are listed in Table 6,and were prepared following the procedure generally described inExamples 168-172 using either silver nano powder 471-W51 (prepared asdescribed in Example 28) or 473-G51 (prepared as described in Example26).

TABLE 6 Formulations for printing with the use of HP Deskjet 690 Ag AgSolution Example sample Concentrate Additives Solvent Comments 173471-W51 30% 0.5% PVP K-30   40% IPA Initial formulation contained   1%Byk-348   5% DPM 60% of Ag and was diluted 7.6% Byk-190   55% water,twice before printing pH = 10 174 471-W51 50% 0.5% PVP K-30   20% NMPInitial formulation contained 0.5% Byk-348 0.04% AMP-95 60% of Ag andwas diluted 1.2 0.5% Tween 20 in water, times before printing 7.6%Byk-190 pH = 10 175 471-W51 40% 0.2% PVP K-30   20% NMP Initialformulation contained   1% Byk-348   1% AMP-95 40% of Ag 7.6% byk-190 inwater, pH = 11.5 176 473-G51 60% 0.2% PVP K-30   20% NMP   1% Byk-348  1% AMP-95 7.6% Byk-190 in water, pH = 11.5 177 473-G51 60% 0.2% PVPK-30   20% n-propanol   1% Byk-348   1% AMP-95 7.6% Byk-190 in water, pH= 11.5 178 473-G51 60% 0.2% PVP K-30   30% NMP   1% Byk-348   1% AMP-957.6% Byk-190 in water, pH = 11.5

Preliminary printing experiments were conducted using a Hewlett-PackardDeskjet 690 printer. Cartridge #29 was washed out withwater/isopropanol/propyleneglycol (60:30:10) and then rinsed withappropriate sample solution. One milliliter of ink was placed into theinternal filter zone of the cartridge and vacuumed via nozzles. Next,the printhead was refilled with 1-2 ml of ink, and printing on paper orpolyimide (“Capton”) was carried out (standard table 5×50, linethickness 0.5 mm). Printed patterns were air-dried.

In general, printed patterns were obtained with several formulations,although after printing about 5-10 pages, a malfunction was observed(either clogging, flow, or wetting problem). The inks described inExamples 176 and 178 yielded the best printed patterns. The inksdescribed in Examples 173 and 174 were printed for several pages, thenit was possible to partially restore the print head by a shortsonication.

EXAMPLES 179-182

Additional compositions were prepared and tested as described above. Theformulations and their properties are listed in Table 7.

TABLE 7 Powder size Surface (D90) Metal Resistivity Sintering ViscosityTension Example Metal (μm) Wt. % Solvent (μΩ cm) Conditions (cPs)(dyne/cm) 179 Ag/Cu 60 30 Butanol 20 300° C., 30 min. 8 180 Ag/Cu 60 51Propyl 23 300° C., 30 min. 3.5 acetate 181 Ag/Cu 60 60 BEA 10 300° C.,30 min. 10 25-28 182 Ag/Cu 60 60 Water/NMP 10 300° C., 30 min. 12 45-50

A number of embodiments of the invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention.Accordingly, other embodiments are within the scope of the followingclaims.

1. A composition comprising 1-70% by weight of a nano metal powderdispersed in a liquid carrier, wherein the composition has a viscosityno greater than about 200 cP at ink jet printing temperatures and is inkjet printable.
 2. A composition acccording to claim 1 comprising 10-60%by weight of the nano metal powder.
 3. A composition according to claim1 comprising 20-60% by weight of the nano metal powder.
 4. A compositionaccording to claim 1 wherein the composition has a viscosity of 1-200 cPat ink jet printing temperatures.
 5. A composition according to claim 1wherein the composition has a viscosity of 1-100 cP at ink jet printingtemperatures.
 6. A composition according to claim 1 wherein thecomposition has a viscosity of 2-20 cP at ink jet printing temperatures.7. A composition according to claim 1 comprising about 60% by weightnano metal powder and having a viscosity of about 18 cP at ink jetprinting temperatures.
 8. A composition according to claim 1 wherein thecomposition has a viscosity no greater than about 200 cP at roomtemperature.
 9. A composition according to claim 1 wherein thecomposition has a viscosity of 1-200 cP at room temperature.
 10. Acomposition according to claim 1 wherein the composition has a viscosityof 1-100 cP at room temperature.
 11. A composition according to claim 1wherein the composition has a viscosity of 2-20 cP at room temperature.12. A composition according to claim 1 comprising about 60% by weightnano metal powder and having a viscosity of about 18 cP at roomtemperature.
 13. A composition according to claim 1 wherein the liquidcarrier comprises water and the composition has a surface tension ofabout 30-60 dynes/cm.
 14. A composition according to claim 1 wherein theliquid carrier comprises an organic solvent and the composition has asurface tension of about 20-37 dynes/cm.
 15. A composition according toclaim 1 wherein the nano metal powder has an average particle size nogreater than about 150 nm.
 16. A composition according to claim 1wherein the nano metal powder has an average particle size no greaterthan about 100 nm.
 17. A composition according to claim 1 wherein thenano metal powder has an average particle size no greater than about 80nm.
 18. A composition according to claim 1 wherein the nano metal powderis prepared according to the MCP process.
 19. A composition according toclaim 1 or 18 wherein the nano metal powder comprises silver.
 20. Acomposition according to claim 1 or 18 wherein the nano metal powdercomprises a silver-copper alloy.
 21. A composition according to claim 18wherein the nano metal powder comprises non-uniform spherical particlesand includes up to about 0.4% by weight aluminum.
 22. A compositionaccording to claim 1 wherein the compositions is stable against particlesettling.
 23. A composition according to claim 1 wherein the liquidcarrier comprises (a) at least one organic solvent and (b) at least oneagent selected from the group consisting of surfactants, wetting agents,rheology modifying agents, adhesion promoters, humectants, binders, andcombinations thereof.
 24. A composition according to claim 1 wherein theliquid carrier comprises (a) water, a water-miscible organic solvent, orcombination thereof and (b) at least one agent selected from the groupconsisting of surfactants, wetting agents, rheology modifying agents,adhesion promoters, humectants, binders, and combinations thereof.
 25. Acomposition according to claim 1 wherein the liquid carrier comprises(a) at least one organic solvent, (b) a curable monomer, and (c) atleast one agent selected from the group consisting of surfactants,wetting agents, rheology modifying agents, adhesion promoters,humectants, binders, and combinations thereof.
 26. A method comprisingprinting the composition of claim 1 onto a substrate using an ink jetprinter.
 27. A method according to claim 26 wherein the ink jet printeris a continuous ink jet printer.
 28. A method according to claim 26wherein the ink jet printer is a drop on demand ink jet printer.
 29. Amethod according to claim 26 wherein the substrate is selected from thegroup consisting of paper, polymer films, textiles, plastics, glass,printed circuit boards, epoxy resins, and combinations thereof.
 30. Amethod according to claim 26 comprising sintering the composition afterapplying it to the substrate.
 31. A method according to claim 26comprising treating the composition after applying it to the substrateby applying electromagnetic radiation, pressure, thermal radiation, or acombination thereof.